Query for checking session wise memory details in oracle database

• How to check session wise memory details in oracle database:

SET lines 300

SET pages 9999

col SESSION format a80

col PID_THREAD format a10

col CURRENT_SIZE format a20

col MAXIMUM_SIZE format a20

SELECT to_char(ssn.sid, '9999') || ' - ' || nvl(ssn.username, nvl(bgp.name, 'background')) ||

 nvl(lower(ssn.machine), ins.host_name) "SESSION",

 to_char(prc.spid, '999999999') "PID_THREAD",

 to_char((se1.value/1024)/1024, '999G999G990D00') || ' MB' "CURRENT_SIZE",

 to_char((se2.value/1024)/1024, '999G999G990D00') || ' MB' "MAXIMUM_SIZE"

FROM v$sesstat se1, v$sesstat se2, v$session ssn, v$bgprocess bgp, v$process prc,

 v$instance ins, v$statname stat1, v$statname stat2

WHERE se1.statistic# = stat1.statistic# and stat1.name = 'session pga memory'

 AND se2.statistic# = stat2.statistic# and stat2.name = 'session pga memory max'

 AND se1.sid = ssn.sid

 AND se2.sid = ssn.sid

 AND ssn.paddr = bgp.paddr (+)

 AND ssn.paddr = prc.addr (+);

• How to check Memory setting in oracle:

col Parameter format a25

select

        con_id, name as Parameter,

        value/1024/1024 as Mbytes

from v$parameter

where name in

        ('pga_aggregate_target',

        'memory_target',

        'memory_max_target',

        'sga_max_size',

        'sga_target',

        'pga_aggregate_limit')

order by name;

• How to check PGA memory usage:

SELECT spid, program,

            pga_max_mem      max,

            pga_alloc_mem    alloc,

            pga_used_mem     used,

            pga_freeable_mem free

FROM V$PROCESS;